1. Field of the Invention
The subject of the invention is an electric motor-driven servo-drive for a motor vehicle lock with an electric drive motor, a servo-drive disk or other servo-drive element which is driven by the electric drive motor, with an operating lever which can be moved back and forth by the servo-drive element between at least two operating positions or another mechanical switching element, and with an electric motor control with which the electric drive motor can be turned on, and which, in a certain free position of the servo-drive element and with simultaneous occurrence of the operating position of the switching element, can be turned off, especially short circuited, there being an electrical or electronic switch which is connected to the electric motor control, which automatically assumes a first position and is influenced by an influencing element into a second position.
2. Description of Related Art
Motor vehicle locks in this sense can be used in many areas, especially as motor vehicle side door locks, rear door locks, rear hatch locks, sliding door locks, hood locks, and the like. In this sense, the term motor vehicle door lock should therefore be understood comparatively comprehensively. In this patent application, the servo-drive disk is described as a servo-drive element, use of all other types of servo-drive elements, for example, also spindle drives, is possible and should also be encompassed by the term servo-drive element. Broad freedom likewise applies to the switching element which is described here as a mechanical operating lever, but which can be a linearly shifted switching element, a swiveling switching element, or also a rotating switching element.
In electric motor-driven servo-drives for motor vehicle locks known from practice, two electrical or electronic switches are connected to the electric motor control, specifically one switch for the servo-drive element and the second switch for the operating lever (U.S. Pat. No. 5,240,296). In the sense of a series connection of the two switches which leads, in terms of computer engineering, to an AND gate, the electric drive motor is turned off when the two switches are activated. Generally, the electric drive motor is turned off by short circuiting it in order to achieve a motor braking action, and thus, rapid shutdown of the servo-drive element (see also German Patent No. 43 34 522).